# Tag Info

The electromagnetic field of a single-wavelength beam (e.g. that of a laser) is sinusoidal with period $\lambda$. e.g. for one dimension E field can be described as follows (ignoring time evolution): $$E = \cos\left(\frac{2\pi}{\lambda}z\right)$$ If you have a second beam that is mutually coherent with the first, the two E-fields can be described as ...